McIntosh MC7270 Vintage Solid State Amplifier - One of our Favorites!
The 7270 is by FAR one of our favorite vintage amps from McIntosh.
Aesthetically it meets all the requirements - large chassis, big blue meters, glass/metal faceplate and BIG power.
This particular sample is in great shape and passed all of our internal tests with ease.
This listing also includes the original wooden cabinet, which is very hard to find in this condition.
Performance Limits are the maximum deviation from perfection permitted for a Mclntosh instrument. We promise you that when you purchase a new MC 7270 from a Mclntosh franchised dealer, it will be capable of or can be made capable of performance at or exceeding these limits or you can return the unit and get your money back. Mclntosh is the only manufacturer that makes this statement.
Mclntosh audio power ratings are in accordance with the Federal Trade Commission Regulation of November 4, 1974 concerning power output claims for amplifiers used in home entertainment products.
270 watts minimum sine wave continuous average power output, per channel, both channels operating into 1 ohm, 2 ohms, 4 ohms, or 8 ohms load impedance, which is:
16.4 volts RMS across 1 ohm
23.2 volts RMS across 2 ohms
32.9 volts RMS across 4 ohms
46.5 volts RMS across 8 ohms
540 watts minimum sine wave continuous average
power output into 2 ohms, 4 ohms, 8 ohms, or 16 ohms load impedance, which is:
32.9 volts RMS across 2 ohms
46.5 volts RMS across 4 ohms
65.7 volts RMS across 8 ohms
93.0 volts RMS across 16 ohms
OUTPUT LOAD IMPEDANCE
1 ohm, 2 ohms, 4 ohms, and 8 ohms; separate terminals
are provided for each output.
2 ohms, 4 ohms, 8 ohms, or 16 ohms, balanced to ground.
RATED POWER BAND
20 Hz to 20,000 Hz
TOTAL HARMONIC DISTORTION
0.02% maximum harmonic distortion at any power level from 250 milliwatts to 270 watts per channel from 20 Hz to 20,000 Hz, both channels operating.
0.02% maximum harmonic distortion at any power level from 250 milliwatts to 540 watts from 20 Hz to 20,000 Hz.
0.02% maximum if instantaneous peak power output is 540 watts or less per channel with both channels operating for any combination of frequencies, 20 Hz to 20,000 Hz,
0.02% maximum if instantaneous peak power output is 1080 watts or less for any combination of frequencies, 20 Hz to 20,000 Hz.
FREQUENCY RESPONSE (AT ONE WATT OUTPUT)
20 Hz to 20,000 Hz +0 -0.25 dB.
10 Hz to 100,00 Hz +0 - 2 dB.
NOISE AND HUM
100 dB below rated output.
Greater than 30
Switchable: 0.75 volt or 2.5 volts-level control provided for higher input voltages.
Clipping is prevented and THD does not exceed 2% with up to 20 dB overdrive a 1 kHz.
120 volts 50/60 Hz; 13 amps.
79 silicon transistors
31 silicon rectifiers and diodes
7 integrated circuits
16 3/16 inches wide (41.1 cm) by 7 1/8 inches high (18.1 cm) by 14 1/2 inches deep (36.8 cm), including connectors. Knob clearance required is 1 1/4 inches (3.2 cm) in front of mounting panel.
The front panel is a combination of glass and black anodized aluminum. The chassis is black.
82 pounds (37.2 kg) net, 96 pounds (43.5 kg) in shipping carton.
The SkyFi Testing Process for Solid State Amplifiers:
We start with a visual inspection of all internal components to make sure there are no signs of stress or aging. Capacitors are checked for telltale sings of bulging or leaking, resistors are checked for signs of overheating or cracking, and transistors are checked for signs of stress or damage.
We then power up the unit carefully and run a simple 1k sine wave while monitoring the output on an oscilloscope for signs of distortion or noise. Finally, we run the amplifier to its full rated power into the appropriate resistive load provided by our Sencore amplifier tester. If there is an issue, it will usually be noticeable at this point. If everything reads clean, we will often test for THD (Total Harmonic Distortion) measured by our Keithley distortion meter, and compare it against the original manufacturers specifications. The amplifier then remains powered on to "burn in" on our test bench for a few hours to make sure there are no heat related issues. If there are balanced inputs available they will be also be tested.
Final testing involves pushing actual music thorough the amplifier. We've learned over time that some issues are only noticeable to a trained ear while listening to familiar source material. Our test bench has reference vintage KEF speakers that we're very familiar with which quickly reveal any discrepancies. Some amplifiers will then move into our listening room where they are tested with our in-house reference speakers of choice.
Please click here for detailed specifics regarding our specialized packing process that separates us from the rest.
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